1. Field of the Invention
The present invention relates to a diagnostic expert system for diagnosing a data processing apparatus itself or a data processing apparatus to control some object, for example, a switching network in an exchange.
2. Description of the Related Art
The following explanation will be given taking a switching network as an example for easy understanding, however, the present invention is not limited to the same. High reliability and efficient operation of a communication network become important issues when providing high level communication services such as a commercial integrated service digital network (ISDN). In particular, rapid fault location and repair is essential because the damage can be great if network service is interrupted, and a powerful fault diagnostics expert system for repair support is required. The present invention proposes a new diagnostic expert system.
When a fault recurs among a variety of units comprising the exchange, generally a fault message is output to, for example, a maintenance console. Then, a diagnostic program corresponding to the fault message is executed Using the result of the executed program, an area causing the fault is determined based on a diagnosis dictionary. Next, a test is carried out for every function to locate a questionable object, e.g., a questionable package, which must then be replaced by a new one Such diagnosis must be completed correctly and rapidly.
In the prior art, as will be explained hereinafter in detail, a maintenance technician watches fault messages displayed on a console. Then he retrieves, according to the displayed contents, a manual book or diagnostic dictionary, so that he can replace packages located in the area where the questionable object is determined to exist, with new packages. Various known electronic parts, such as integrated circuits (IC's), are mounted on each package. With new package, a corresponding diagnostic command is input to make a diagnosis. The diagnosis is carried out repeatedly, and if the result is successful, the faulty package or packages can be replaced by a new one or new ones Finally the maintenance technicians introduce the new packages into the apparatus, to be diagnosed by the use of a so-called in-service command.
In actuality, the contents of the manual book and the diagnostic dictionary become complicated along with an increase of the size of the switching network system. Thus, it is not easy for the maintenance technicians to locate a fault based on the complicated diagnostic results. This makes it impossible to achieve rapid detection of the questionable package.
A diagnostic expert system has been proposed in which knowledge based on a maintenance technician's experience is expressed in an "IF-THEN" guided program through which knowledge relating to fault conditions is retrieved by the use of a reasoning engine. A questionable object is then located by using the retrieved knowledge.
As a first prior art example, Japanese Unexamined Patent Publication No. 61(1986)-55777 proposes diagnosis achieved by utilizing a diagnostic rule. As a second prior art example, Japanese Unexamined Patent Publication No. 62(1987)-175060 proposes diagnosis by utilizing a diagnostic knowledge data base which corresponds to a first knowledge data base according to the present invention, in which a maintenance technician's knowledge is contained.
In the prior art diagnostic expert systems, there is a first problem in that it is impossible to make a diagnosis regarding a fault which has never been experienced by a maintenance technician. A second problem is that it takes a very long time for a maintenance technician to locate a fault if the fault occurs outside the area which he can cover.